1 /* 2 * linux/arch/arm/kernel/module.c 3 * 4 * Copyright (C) 2002 Russell King. 5 * Modified for nommu by Hyok S. Choi 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Module allocation method suggested by Andi Kleen. 12 */ 13 #include <linux/module.h> 14 #include <linux/moduleloader.h> 15 #include <linux/kernel.h> 16 #include <linux/mm.h> 17 #include <linux/elf.h> 18 #include <linux/vmalloc.h> 19 #include <linux/fs.h> 20 #include <linux/string.h> 21 #include <linux/gfp.h> 22 23 #include <asm/pgtable.h> 24 #include <asm/sections.h> 25 #include <asm/smp_plat.h> 26 #include <asm/unwind.h> 27 28 #ifdef CONFIG_XIP_KERNEL 29 /* 30 * The XIP kernel text is mapped in the module area for modules and 31 * some other stuff to work without any indirect relocations. 32 * MODULES_VADDR is redefined here and not in asm/memory.h to avoid 33 * recompiling the whole kernel when CONFIG_XIP_KERNEL is turned on/off. 34 */ 35 #undef MODULES_VADDR 36 #define MODULES_VADDR (((unsigned long)_etext + ~PGDIR_MASK) & PGDIR_MASK) 37 #endif 38 39 #ifdef CONFIG_MMU 40 void *module_alloc(unsigned long size) 41 { 42 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END, 43 GFP_KERNEL, PAGE_KERNEL_EXEC, -1, 44 __builtin_return_address(0)); 45 } 46 #else /* CONFIG_MMU */ 47 void *module_alloc(unsigned long size) 48 { 49 return size == 0 ? NULL : vmalloc(size); 50 } 51 #endif /* !CONFIG_MMU */ 52 53 void module_free(struct module *module, void *region) 54 { 55 vfree(region); 56 } 57 58 int module_frob_arch_sections(Elf_Ehdr *hdr, 59 Elf_Shdr *sechdrs, 60 char *secstrings, 61 struct module *mod) 62 { 63 return 0; 64 } 65 66 int 67 apply_relocate(Elf32_Shdr *sechdrs, const char *strtab, unsigned int symindex, 68 unsigned int relindex, struct module *module) 69 { 70 Elf32_Shdr *symsec = sechdrs + symindex; 71 Elf32_Shdr *relsec = sechdrs + relindex; 72 Elf32_Shdr *dstsec = sechdrs + relsec->sh_info; 73 Elf32_Rel *rel = (void *)relsec->sh_addr; 74 unsigned int i; 75 76 for (i = 0; i < relsec->sh_size / sizeof(Elf32_Rel); i++, rel++) { 77 unsigned long loc; 78 Elf32_Sym *sym; 79 const char *symname; 80 s32 offset; 81 #ifdef CONFIG_THUMB2_KERNEL 82 u32 upper, lower, sign, j1, j2; 83 #endif 84 85 offset = ELF32_R_SYM(rel->r_info); 86 if (offset < 0 || offset > (symsec->sh_size / sizeof(Elf32_Sym))) { 87 pr_err("%s: section %u reloc %u: bad relocation sym offset\n", 88 module->name, relindex, i); 89 return -ENOEXEC; 90 } 91 92 sym = ((Elf32_Sym *)symsec->sh_addr) + offset; 93 symname = strtab + sym->st_name; 94 95 if (rel->r_offset < 0 || rel->r_offset > dstsec->sh_size - sizeof(u32)) { 96 pr_err("%s: section %u reloc %u sym '%s': out of bounds relocation, offset %d size %u\n", 97 module->name, relindex, i, symname, 98 rel->r_offset, dstsec->sh_size); 99 return -ENOEXEC; 100 } 101 102 loc = dstsec->sh_addr + rel->r_offset; 103 104 switch (ELF32_R_TYPE(rel->r_info)) { 105 case R_ARM_NONE: 106 /* ignore */ 107 break; 108 109 case R_ARM_ABS32: 110 *(u32 *)loc += sym->st_value; 111 break; 112 113 case R_ARM_PC24: 114 case R_ARM_CALL: 115 case R_ARM_JUMP24: 116 offset = (*(u32 *)loc & 0x00ffffff) << 2; 117 if (offset & 0x02000000) 118 offset -= 0x04000000; 119 120 offset += sym->st_value - loc; 121 if (offset & 3 || 122 offset <= (s32)0xfe000000 || 123 offset >= (s32)0x02000000) { 124 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 125 module->name, relindex, i, symname, 126 ELF32_R_TYPE(rel->r_info), loc, 127 sym->st_value); 128 return -ENOEXEC; 129 } 130 131 offset >>= 2; 132 133 *(u32 *)loc &= 0xff000000; 134 *(u32 *)loc |= offset & 0x00ffffff; 135 break; 136 137 case R_ARM_V4BX: 138 /* Preserve Rm and the condition code. Alter 139 * other bits to re-code instruction as 140 * MOV PC,Rm. 141 */ 142 *(u32 *)loc &= 0xf000000f; 143 *(u32 *)loc |= 0x01a0f000; 144 break; 145 146 case R_ARM_PREL31: 147 offset = *(u32 *)loc + sym->st_value - loc; 148 *(u32 *)loc = offset & 0x7fffffff; 149 break; 150 151 case R_ARM_MOVW_ABS_NC: 152 case R_ARM_MOVT_ABS: 153 offset = *(u32 *)loc; 154 offset = ((offset & 0xf0000) >> 4) | (offset & 0xfff); 155 offset = (offset ^ 0x8000) - 0x8000; 156 157 offset += sym->st_value; 158 if (ELF32_R_TYPE(rel->r_info) == R_ARM_MOVT_ABS) 159 offset >>= 16; 160 161 *(u32 *)loc &= 0xfff0f000; 162 *(u32 *)loc |= ((offset & 0xf000) << 4) | 163 (offset & 0x0fff); 164 break; 165 166 #ifdef CONFIG_THUMB2_KERNEL 167 case R_ARM_THM_CALL: 168 case R_ARM_THM_JUMP24: 169 upper = *(u16 *)loc; 170 lower = *(u16 *)(loc + 2); 171 172 /* 173 * 25 bit signed address range (Thumb-2 BL and B.W 174 * instructions): 175 * S:I1:I2:imm10:imm11:0 176 * where: 177 * S = upper[10] = offset[24] 178 * I1 = ~(J1 ^ S) = offset[23] 179 * I2 = ~(J2 ^ S) = offset[22] 180 * imm10 = upper[9:0] = offset[21:12] 181 * imm11 = lower[10:0] = offset[11:1] 182 * J1 = lower[13] 183 * J2 = lower[11] 184 */ 185 sign = (upper >> 10) & 1; 186 j1 = (lower >> 13) & 1; 187 j2 = (lower >> 11) & 1; 188 offset = (sign << 24) | ((~(j1 ^ sign) & 1) << 23) | 189 ((~(j2 ^ sign) & 1) << 22) | 190 ((upper & 0x03ff) << 12) | 191 ((lower & 0x07ff) << 1); 192 if (offset & 0x01000000) 193 offset -= 0x02000000; 194 offset += sym->st_value - loc; 195 196 /* 197 * For function symbols, only Thumb addresses are 198 * allowed (no interworking). 199 * 200 * For non-function symbols, the destination 201 * has no specific ARM/Thumb disposition, so 202 * the branch is resolved under the assumption 203 * that interworking is not required. 204 */ 205 if ((ELF32_ST_TYPE(sym->st_info) == STT_FUNC && 206 !(offset & 1)) || 207 offset <= (s32)0xff000000 || 208 offset >= (s32)0x01000000) { 209 pr_err("%s: section %u reloc %u sym '%s': relocation %u out of range (%#lx -> %#x)\n", 210 module->name, relindex, i, symname, 211 ELF32_R_TYPE(rel->r_info), loc, 212 sym->st_value); 213 return -ENOEXEC; 214 } 215 216 sign = (offset >> 24) & 1; 217 j1 = sign ^ (~(offset >> 23) & 1); 218 j2 = sign ^ (~(offset >> 22) & 1); 219 *(u16 *)loc = (u16)((upper & 0xf800) | (sign << 10) | 220 ((offset >> 12) & 0x03ff)); 221 *(u16 *)(loc + 2) = (u16)((lower & 0xd000) | 222 (j1 << 13) | (j2 << 11) | 223 ((offset >> 1) & 0x07ff)); 224 break; 225 226 case R_ARM_THM_MOVW_ABS_NC: 227 case R_ARM_THM_MOVT_ABS: 228 upper = *(u16 *)loc; 229 lower = *(u16 *)(loc + 2); 230 231 /* 232 * MOVT/MOVW instructions encoding in Thumb-2: 233 * 234 * i = upper[10] 235 * imm4 = upper[3:0] 236 * imm3 = lower[14:12] 237 * imm8 = lower[7:0] 238 * 239 * imm16 = imm4:i:imm3:imm8 240 */ 241 offset = ((upper & 0x000f) << 12) | 242 ((upper & 0x0400) << 1) | 243 ((lower & 0x7000) >> 4) | (lower & 0x00ff); 244 offset = (offset ^ 0x8000) - 0x8000; 245 offset += sym->st_value; 246 247 if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS) 248 offset >>= 16; 249 250 *(u16 *)loc = (u16)((upper & 0xfbf0) | 251 ((offset & 0xf000) >> 12) | 252 ((offset & 0x0800) >> 1)); 253 *(u16 *)(loc + 2) = (u16)((lower & 0x8f00) | 254 ((offset & 0x0700) << 4) | 255 (offset & 0x00ff)); 256 break; 257 #endif 258 259 default: 260 printk(KERN_ERR "%s: unknown relocation: %u\n", 261 module->name, ELF32_R_TYPE(rel->r_info)); 262 return -ENOEXEC; 263 } 264 } 265 return 0; 266 } 267 268 int 269 apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab, 270 unsigned int symindex, unsigned int relsec, struct module *module) 271 { 272 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n", 273 module->name); 274 return -ENOEXEC; 275 } 276 277 struct mod_unwind_map { 278 const Elf_Shdr *unw_sec; 279 const Elf_Shdr *txt_sec; 280 }; 281 282 static const Elf_Shdr *find_mod_section(const Elf32_Ehdr *hdr, 283 const Elf_Shdr *sechdrs, const char *name) 284 { 285 const Elf_Shdr *s, *se; 286 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 287 288 for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) 289 if (strcmp(name, secstrs + s->sh_name) == 0) 290 return s; 291 292 return NULL; 293 } 294 295 extern void fixup_pv_table(const void *, unsigned long); 296 extern void fixup_smp(const void *, unsigned long); 297 298 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 299 struct module *mod) 300 { 301 const Elf_Shdr *s = NULL; 302 #ifdef CONFIG_ARM_UNWIND 303 const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 304 const Elf_Shdr *sechdrs_end = sechdrs + hdr->e_shnum; 305 struct mod_unwind_map maps[ARM_SEC_MAX]; 306 int i; 307 308 memset(maps, 0, sizeof(maps)); 309 310 for (s = sechdrs; s < sechdrs_end; s++) { 311 const char *secname = secstrs + s->sh_name; 312 313 if (!(s->sh_flags & SHF_ALLOC)) 314 continue; 315 316 if (strcmp(".ARM.exidx.init.text", secname) == 0) 317 maps[ARM_SEC_INIT].unw_sec = s; 318 else if (strcmp(".ARM.exidx.devinit.text", secname) == 0) 319 maps[ARM_SEC_DEVINIT].unw_sec = s; 320 else if (strcmp(".ARM.exidx", secname) == 0) 321 maps[ARM_SEC_CORE].unw_sec = s; 322 else if (strcmp(".ARM.exidx.exit.text", secname) == 0) 323 maps[ARM_SEC_EXIT].unw_sec = s; 324 else if (strcmp(".ARM.exidx.devexit.text", secname) == 0) 325 maps[ARM_SEC_DEVEXIT].unw_sec = s; 326 else if (strcmp(".init.text", secname) == 0) 327 maps[ARM_SEC_INIT].txt_sec = s; 328 else if (strcmp(".devinit.text", secname) == 0) 329 maps[ARM_SEC_DEVINIT].txt_sec = s; 330 else if (strcmp(".text", secname) == 0) 331 maps[ARM_SEC_CORE].txt_sec = s; 332 else if (strcmp(".exit.text", secname) == 0) 333 maps[ARM_SEC_EXIT].txt_sec = s; 334 else if (strcmp(".devexit.text", secname) == 0) 335 maps[ARM_SEC_DEVEXIT].txt_sec = s; 336 } 337 338 for (i = 0; i < ARM_SEC_MAX; i++) 339 if (maps[i].unw_sec && maps[i].txt_sec) 340 mod->arch.unwind[i] = 341 unwind_table_add(maps[i].unw_sec->sh_addr, 342 maps[i].unw_sec->sh_size, 343 maps[i].txt_sec->sh_addr, 344 maps[i].txt_sec->sh_size); 345 #endif 346 #ifdef CONFIG_ARM_PATCH_PHYS_VIRT 347 s = find_mod_section(hdr, sechdrs, ".pv_table"); 348 if (s) 349 fixup_pv_table((void *)s->sh_addr, s->sh_size); 350 #endif 351 s = find_mod_section(hdr, sechdrs, ".alt.smp.init"); 352 if (s && !is_smp()) 353 fixup_smp((void *)s->sh_addr, s->sh_size); 354 return 0; 355 } 356 357 void 358 module_arch_cleanup(struct module *mod) 359 { 360 #ifdef CONFIG_ARM_UNWIND 361 int i; 362 363 for (i = 0; i < ARM_SEC_MAX; i++) 364 if (mod->arch.unwind[i]) 365 unwind_table_del(mod->arch.unwind[i]); 366 #endif 367 } 368